1. Field of the Invention
The present invention is related to a system for refreshing a dynamic memory. More particularly, the present invention is related to a novel refresh clock system which enables a processing system to be stopped and to save the state of the system.
2. Description of the Prior Art
Modern computing systems are extremely sophisticated and are designed to recognize certain problems which cause interrupts or a desire to shutdown the system for analysis and maintenance. When such a system problem arises, it is desirable to be able to save the state of the latches in the memory unit and retain the data that is currently stored in the dynamic memory. If memory data is dumped before the latches are scanned, the state of the latches is changed and its original state is lost irretrievably. However, if the latches are first scanned before dumping memory data, the refresh clock signal to the memory is shut off so that memory data is lost. While the latches are being scanned, the contents (data) of the memory would be lost. It would be desirable to provide an unconditional clock and automatic refresh logic system which would permit the latches to be scanned while the memory is continuously refreshed, preserving the original contents of the memory for diagnostic purposes.